/**
 * @file sha2.h
 *
 * @brief SHA-224 and SHA-256 cryptographic hash function
 *
 * Copyright (C) 2006-2010, Brainspark B.V.
 *
 * This file is part of PolarSSL (http://www.polarssl.org)
 * Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
 *
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
#ifndef POLARSSL_SHA2_H
#define POLARSSL_SHA2_H

#include <string.h>

#define POLARSSL_SHA2_C 1
//#define POLARSSL_SELF_TEST	1
#define POLARSSL_ERR_SHA2_FILE_IO_ERROR -0x0078 /**< Read/write error in file. */
#define SHA256TYPE 0
#define SHA244TYPE 1
/**
 * @brief SHA-256 context structure
 */
typedef struct {
	unsigned long total[2];   /*!< number of bytes processed */
	unsigned long state[8];   /*!< intermediate digest state */
	unsigned char buffer[64]; /*!< data block being processed */

	unsigned char ipad[64]; /*!< HMAC: inner padding */
	unsigned char opad[64]; /*!< HMAC: outer padding */
	int is224;              /*!< 0 => SHA-256, else SHA-224 */
} sha2_context;

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @brief SHA-256 context setup
 *
 * @param ctx context to be initialized
 * @param is224 0 = use SHA256, 1 = use SHA224
 */
void sha2_starts(sha2_context *ctx, int is224);

/**
 * @brief SHA-256 process buffer
 *
 * @param ctx SHA-256 context
 * @param input buffer holding the data
 * @param ilen length of the input data
 */
void sha2_update(sha2_context *ctx, const unsigned char *input, size_t ilen);

/**
 * @brief SHA-256 final digest
 *
 * @param ctx SHA-256 context
 * @param output SHA-224/256 checksum result
 */
void sha2_finish(sha2_context *ctx, unsigned char output[32]);

/**
 * @brief Output = SHA-256( input buffer )
 *
 * @param input buffer holding the data
 * @param ilen length of the input data
 * @param output SHA-224/256 checksum result
 * @param is224 0 = use SHA256, 1 = use SHA224
 */
void sha2(const unsigned char *input, size_t ilen, unsigned char output[32], int is224);

/**
 * @brief Output = SHA-256( file contents )
 *
 * @param path input file name
 * @param output SHA-224/256 checksum result
 * @param is224 0 = use SHA256, 1 = use SHA224
 *
 * @return 0 if successful, or POLARSSL_ERR_SHA2_FILE_IO_ERROR
 */
int sha2_file(const char *path, unsigned char output[32], int is224);

/**
 * @brief SHA-256 HMAC context setup
 *
 * @param ctx HMAC context to be initialized
 * @param key HMAC secret key
 * @param keylen length of the HMAC key
 * @param is224 0 = use SHA256, 1 = use SHA224
 */
void sha2_hmac_starts(sha2_context *ctx, const unsigned char *key, size_t keylen, int is224);

/**
 * @brief SHA-256 HMAC process buffer
 *
 * @param ctx HMAC context
 * @param input buffer holding the data
 * @param ilen length of the input data
 */
void sha2_hmac_update(sha2_context *ctx, const unsigned char *input, size_t ilen);

/**
 * @brief SHA-256 HMAC final digest
 *
 * @param ctx HMAC context
 * @param output SHA-224/256 HMAC checksum result
 */
void sha2_hmac_finish(sha2_context *ctx, unsigned char output[32]);

/**
 * @brief SHA-256 HMAC context reset
 *
 * @param ctx HMAC context to be reset
 */
void sha2_hmac_reset(sha2_context *ctx);

/**
 * @brief Output = HMAC-SHA-256( hmac key, input buffer )
 *
 * @param key HMAC secret key
 * @param keylen length of the HMAC key
 * @param input buffer holding the data
 * @param ilen length of the input data
 * @param output HMAC-SHA-224/256 result
 * @param is224 0 = use SHA256, 1 = use SHA224
 */
void sha2_hmac(const unsigned char *key, size_t keylen, const unsigned char *input, size_t ilen,
               unsigned char output[32], int is224);

/**
 * @brief Checkup routine
 *
 * @return 0 if successful, or 1 if the test failed
 */
int sha2_self_test(int verbose);

#ifdef __cplusplus
}
#endif

#endif /* sha2.h */
